1 files changed, 95 insertions, 0 deletions
diff --git a/engines/sci/engine/intmap.h b/engines/sci/engine/intmap.h
new file mode 100644
index 0000000000..fe00fa8621
--- /dev/null
+++ b/engines/sci/engine/intmap.h
@@ -0,0 +1,95 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * $URL$
+ * $Id$
+ *
+ */
+
+#ifndef SCI_INTMAP_H
+#define SCI_INTMAP_H
+
+#include "common/scummsys.h"
+
+namespace Sci {
+
+
+
+
+// Assumes that the ints are relatively evenly distributed
+enum {
+	DCS_INT_HASH_MAX = 256
+};
+
+/**
+ * Defines a map from arbitrary integers to "small" integers, useable as index
+ * into small arrays. This class is somewhat like a hashmap, but not quite:
+ * Unlike a hashmap, it generates the values associated to each key. It does
+ * not try to be very clever about it, either, e.g. using a linked list of
+ * values to keep track of what is mapped where.
+ * Another important feature is that it reclaims unused values when they
+ * are removed.
+ *
+ * All in all, this implementation is not very elegant, and wastes memory.
+ * But it does the job. Any rewrite of this class would have to provide a
+ * way to load the old savegames made using the current implementation.
+ */
+struct IntMapper {
+
+	struct Node {
+		int key;
+		int idx;
+		Node *next;
+	};
+
+	int base_value;  // Starts at zero, counts upwards
+	Node *nodes[DCS_INT_HASH_MAX];
+	Node *holes; /* List of freed entries to minimize
+				     ** memory operations and modifications
+				     ** to base_value  */
+
+	void free_node_recursive(Node *node);
+
+public:
+	IntMapper();
+	~IntMapper();
+
+	/**
+	 * Checks whether a key is in the map, adds it if neccessary.
+	 * @param value		The key to check for/add
+	 * @param add		Whether to add the key if it's not in there
+	 * @param was_added	Set to non-zero if and only if the key is new, ignored if NULL.
+	 * @return The new (or old) index, or -1 if add was zero and
+	 *                   the key couldn't be found
+	 */
+	int checkKey(int key, bool add, bool *wasAdded = 0);
+
+	/**
+	 * Removes a key from the map.
+	 * @param key		The key to remove
+	 * @return	The index of the key, or -1 if it wasn't present
+	 */
+	int removeKey(int key);
+
+};
+
+} // End of namespace Sci
+
+#endif // SCI_INTMAP_H